MS student researches
seismic design of deep bridge pier foundations
Coming from Wisconsin, graduate
student Aaron Shelman is not afraid of the cold. In
fact, he likes it so much that he is using liquid
nitrogen to create subzero temperatures year round.
As a civil engineering graduate student with an
emphasis in structural engineering, Aaron has been
researching the effects of seasonal freezing on
soil-foundation-structure-interaction.
Aaron’s major professor, Dr.
Sri Sritharan, introduced him to the need for more
research and better construction of bridge columns
that extend into the ground and act as foundations.
The main research objective is to design these
foundations to withstand seismic activity under both
warm and wintry conditions, which are experienced in
several seismic regions of the country. This is
especially important because some of the largest
earthquakes in the history of the United States—such
as the 1811-1812 New Madrid series of earthquakes
and 1964 Great Alaska earthquake—have occurred
during winter months.
Funded by the Alaska University
Transportation Center and the Alaska Department of
Transportation and Public Facilities, his research
has examined how these columns will respond to
movements in the earth when subjected to seasonal
freezing. Aaron’s focus is on the development of an
analysis model that can account for the changes in
material properties in this frozen state and their
impact on seismic response of the foundations and
bridges. In the lab, he has been running tests on
confined concrete samples at cold temperatures to
examine their structural properties and comparing
them with current models developed for warm
conditions. The idea is to ensure that concrete
“goes with the flow” at all temperatures, so that
structures will maintain the same weight bearing
capacity but can withstand the large movements
typically associated with earthquake loading. His
labors will result in safer, more reliable
construction of these types of columns in the
future.
A graduate of the University of
Wisconsin Platteville with a BS in civil
engineering, Aaron was drawn to Iowa State’s
graduate engineering programs by the opportunities
that would be available to him. Some of his peers
from Platteville had already begun their graduate
work at ISU, and he was especially impressed by the
Civil, Construction and Environmental Engineering
Department. He thinks one of the best things about
his experience has been expanding his knowledge
through his coursework and by observing his peers’
research in other areas of civil engineering.
Aaron will finish his master’s
degree this semester and plans to immediately begin
a doctorate in civil engineering with an emphasis in
structural engineering.
As part of his thesis he has created an
analysis method for structures in cohesive soils
because that is where the largest deficiency in
current practice exists. As he continues his
graduate career at Iowa State he will expand his
research to examine how this issue applies in other
soil and foundation types.
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